Inflorescence and flower development in wild-type and sid mutant Melilotus alba, white sweetclover

White sweetclover, Melilotus alba Desr. (Fabaceae), produces white, papilionoid flowers on a simple raceme. Individual floral apices originate in the axil of a bract. Each flower consists of five alternating whorls that, from outside to inside, consist of (i) five sepals, (ii) five petals, of which two fuse along their abaxial edges to form the keel, (iii) five antesepalous stamens, (iv) five antepetalous stamens with shorter filaments, and (v) a single carpel containing two to four ovules. The development of the wild-type sweetclover inflorescence and flowers is described in detail and compared with a mutant in which secondary inflorescences, instead of individual flowers, developed in axils of the bracts, especially at the base of the inflorescence. This white sweetclover mutant, designated sid for "secondary inflorescence development", might serve as a test of the ABC model of floral development, which was based on the model plants Antirrhinum and Arabidopsis.Key words: white sweetclover, inflorescence, flower, development, sid mutant.

Photoperiod and Gibberellic Acid Modify Growth and Flowering of Craspedia Globosa

The objective of this study was to investigate the influence of photoperiod and 0, 1, 5, or 10 applications at weekly intervals of GA3 foliar sprays at 500 mg·liter–1 on growth and flowering of Craspedia globosa `Drumstick' Benth. Long days (LD) hastened flowering and increased the number of flowers per plant. Short days (SD) increased foliage height and foliage fresh and dry weights. Foliage and total plant heights increased and days to bud and secondary inflorescence width decreased linearly as GA3 application frequency increased. Chemical name used: (1α,2β,4aα,4bβ,10β)-2,4a,7-trihydroxy-1-methyl-8-methylen egibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (gibberellic acid, GA3).

Organogenesis of the male inflorescence and flowers of Myrica esculenta

Organogenesis of the male inflorescence and flowers of Myrica esculenta is described. The inflorescence is a panicle of spikes. The myricaceous flower consists of up to five stamens and two transversal bracts. The organography and organogenesis of the flowers of the distal region of the inflorescence are similar to the organography and organogenesis of the flowers of the secondary inflorescence axes in the intermediate region of the inflorescence. The presence of a transversal pair of bracts on the floral axis is variable. Only in monostaminate flowers does a stamen terminate an axis. This is a function of the monostaminate flower being positioned at the extreme distal region of the primary inflorescence or secondary inflorescence axis. Five-, four-, three-, and two-stamened flowers occur as an acropetal reduction series along the primary inflorescence or secondary inflorescence axis. Whether or not floral bracts are present, the stamens arise simultaneously in a whorl on the flank of a flattened floral apex. The stamens do not form in the axils of the floral bracts. The pattern of male flower development is the same in all other species examined. It is concluded that this pattern of flower development illustrates a conservative sequence of ontogenetic events within the family. This is of taxonomic and phylogenetic significance.